Riverbank Erosion in the Bengal Delta: An Integrated Perspective (Springer Geography)

This book discusses the issue of riverbank erosion and its associated causes, risks and social challenges in the Bengal Delta. The book covers the physical processes and indicators of riverbank erosion such as sediment flux and channel morphology, the anthropogenic and natural causes of erosion, the social consequences that afflict vulnerable communities who depend on the delta for their livelihoods, and potential solutions to harmful erosion processes such as bioengineering methods and increased community governance through a socio-hydrological approach. Though the Bengal Delta is one of the most populated regions in the world, few publications exist that discuss riverbank erosion as a major threat to environmental and livelihood sustainability in a comprehensive manner. The book will fill this gap in research for students and researchers in geography and environmental sciences, and will engage regional planners, decision makers and policy makers to further their understanding of the complex social and environmental aspects of the Bengal Delta associated with persistent and worsening riverbank erosion. Foreword Preface Scientific Notations Conversion Table Length Area Volume Weight About the Book Contents About the Authors Abbreviations List of Figures List of Tables PartPart10005730123 Chapter 1: Riverbank Erosion: Basic Concepts and Approaches 1.1 Conceptual Outlook of Riverbank Erosion 1.2 Historical Perspective of Bank Erosion Hazard Studies 1.2.1 Trajectory of Bank Erosion Research 1.2.2 Approaches to Bank Erosion Study 1.3 Dimensions of Riverbank Erosion Research 1.4 Interdisciplinary Nature of Riverbank Erosion 1.5 Scales in Riverbank Erosion Study References Chapter 2: Context of Riverbank Erosion 2.1 Backdrop 2.2 Global Perspective on Riverbank Erosion 2.3 Regional Perspective on River Bank Erosion in the Bengal Delta 2.4 The State of the Art of Bank Erosion Research in the Bengal Delta 2.5 Present Study: Needs and Focus References PartPart20005730124 Chapter 3: Riverbank Erosion: A Natural Process 3.1 Riverbank Erosion: A Natural Geoecological Process 3.2 Types and Mechanisms of Bank Erosion 3.2.1 Mechanism of Bank Erosion: World Scenario 3.2.2 Bank Erosion Scenario of Bengal Delta 3.3 Riverbank Erosion Factors 3.3.1 Erodibility Factors 3.3.2 Erosivity Factors 3.3.2.1 Erosivity Under Monsoon Regime 3.3.2.2 Tidal Upsurge and Storm Surge 3.3.2.3 Variable River Regime 3.4 Measurement of Riverbank Erosion 3.4.1 Field Techniques 3.4.1.1 Erosion Pin 3.4.1.2 Photo Electronic Erosion Pin (PEEP) and PEET-3T 3.4.1.3 Total Station and Terrestrial Laser Scanner 3.4.2 Existing Models on River Bank Erosion 3.4.2.1 Bank Assessment of Non-point Source Consequence of Sediment (BANCS) 3.4.2.2 The Bank Stability and Toe Erosion Model (BSTEM) 3.4.2.3 The Bank Stability Model (BSM) 3.4.2.4 Toe Erosion Model (TEM) 3.4.2.5 Dynamic SedNet Stream Bank Erosion Model 3.4.2.6 Numerical Modelling Using DSAS Model 3.4.2.7 Generalized Model of Quantitative Assessment of River Bank Erosion Across the Cross-Sections 3.4.3 Empirical Measurements of Bank Erosion 3.4.3.1 Bankline Shifting Using DSAS Model in the Bengal Delta 3.4.3.2 Quantitative Assessment of Bank Erosion Along the Cross Sections of Bhagirathi River References Chapter 4: Riverbank Erosion: A Human-Induced Process 4.1 Regulated River Regime and Bank Erosion 4.1.1 Farakka Barrage Project: A Mega-scale Intervention 4.1.2 Decrease of Lean Period Discharge in the Post-Farakka Period and Bank Erosion in Bangladesh 4.1.3 Increase of Lean Period Discharge in the Post-Farakka Period and Bank Erosion in India 4.1.4 Fluctuation in River Regime Through Controlled Hydrology 4.2 Land Use and Cover Changes and Bank Erosion 4.2.1 Impact of Bank Erosion on Land Use and Cover Changes 4.2.1.1 Basin-Scale Analysis 4.2.1.2 Site-Specific Analysis 4.2.2 Impact of Land Use on Channel Instability and Bank Erosion 4.3 Other Anthropogenic Drivers of Bank Erosion 4.3.1 Brickfields and Sediment Flux 4.3.2 Road Stream Crossing and Channel Changes 4.3.3 Guide Bank and Sedimentation 4.3.4 Vessel Movements and Bank Failure References PartPart30005730125 Chapter 5: Riverbank Erosion and Channel Morphology 5.1 Channel Planform Changes 5.1.1 Channel Oscillation and Meandering in Bengal Basin 5.1.1.1 Oscillatory Behaviour and Meander Deformation 5.1.1.2 Stream Meandering and Sinuosity 5.1.2 Stream Meandering and Meander Geometry for the Bhagirathi River 5.1.2.1 Pattern of Meandering 5.1.2.2 Geometry of Stream Meandering 5.1.3 Channel Braiding in the Bengal Basin 5.1.3.1 General Nature of Braiding Indices 5.1.3.2 Case Studies from Bengal Basin 5.2 Channel Cross-sectional Changes 5.2.1 Channel Geometry 5.2.1.1 Width-Depth Ratio 5.2.1.2 Width Index 5.2.1.3 Depth Index 5.2.1.4 Channel Efficiency Index 5.2.2 Analysis of Channel Asymmetry 5.2.2.1 Measuring Channel Asymmetry 5.2.2.2 Pattern of Asymmetry Indices References Chapter 6: Economic Vulnerabilities Induced by Riverbank Erosion 6.1 Introduction 6.2 Conceptual Framework on Resource Base, Economy, and Livelihood 6.2.1 Resource Base and Economy 6.2.2 Shifting of Economic Activity 6.2.3 Rural Livelihood and Its Change 6.3 Change in the Asset Profile 6.3.1 Nature of Land Loss 6.3.2 Loss of Agricultural and Settlement Land 6.3.3 Bank Erosion and Displacement 6.3.4 Selling of Properties and Assets 6.4 Change in Income Portfolio 6.4.1 Sources of Income 6.4.2 Distribution of Income 6.5 Poverty Assessment 6.5.1 Techniques for Measuring Poverty 6.5.1.1 Head Count Index 6.5.1.2 Poverty Gap Index 6.5.1.3 Poverty Severity Index 6.5.2 Analysis of Poverty 6.6 Occupational Change and Livelihood Diversification 6.6.1 Nature of Diversification 6.6.2 Measurement of Diversification 6.6.2.1 Inverse Herfindahl-Hirschman Index 6.6.2.2 Individual Occupational Diversification Index 6.6.3 Assessment of Factors 6.7 Multivariate Analysis of Livelihood Vulnerability 6.7.1 Variable-Wise Analysis (R- mode Analysis) 6.7.2 Region-Wise Analysis (Q-mode Analysis) 6.7.3 Livelihood Vulnerability Among Various Income Groups 6.8 Impact on Agricultural Activities 6.8.1 Agriculture in West Bengal 6.8.1.1 Cropping Intensity 6.8.1.2 Crop Diversity 6.8.1.3 Agricultural Productivity 6.8.1.4 Commercialization of Agriculture 6.8.1.5 Critical Appreciation of Mainland and Charland Agriculture in West Bengal and Bangladesh 6.9 Recent Changes in the Economic Landscape References Chapter 7: Social Instabilities Induced by Riverbank Erosion 7.1 Backdrop 7.2 Changes in Social Institutions 7.2.1 Family 7.2.2 Kinship 7.2.3 Education 7.2.4 Healthcare 7.2.5 Government 7.3 Social Processes and Social Relation in Hazardous Space 7.3.1 Measuring the Social Processes 7.3.2 Pattern of Social Processes 7.3.2.1 Intraindividual Processes 7.3.2.2 Interpersonal Processes 7.3.2.3 Intergroup Processes 7.3.2.4 Group Processes 7.3.3 Association of Social Processes 7.4 Social Psychological Effects of Bank Erosion Hazard 7.5 Social Psychology of Desire 7.6 Emic and Etic Perspectives of Bank Erosion 7.6.1 Perception of Women 7.6.2 Perception of Economic Migrants 7.6.3 Perception of Permanent Migrants 7.6.4 Perception of School Teachers Coming from Outside (Etic Perspective) 7.6.5 Perception of Outside People and Relatives (Etic Perspective) 7.7 Emergence of Charland and Critical Social Process 7.7.1 Backdrop and Rationale 7.7.2 Study Design 7.7.3 Study Findings and Analysis 7.7.3.1 Evolution of Mid-Channel Bar into the Bank-Attached Bar 7.7.3.2 Evolution of Char and Social Instability References PartPart40005730126 Chapter 8: Coping Strategies: Towards a Resilient Society 8.1 Swimming Against the Tide 8.2 Existing Strategies at the Individual and Community Level 8.2.1 Individual and Community Initiatives in West Bengal 8.2.2 Individual and Community Initiatives in Bangladesh 8.3 Controlling Measures (Engineering) 8.3.1 Civil Engineering Measures 8.3.1.1 Major Civil Engineering Structures 8.3.1.2 Civil Engineering in West Bengal 8.3.1.3 Civil Engineering in Bangladesh 8.3.2 Bio-engineering/Bio-technical Measures 8.4 Alternative Mitigation Measures (Social Engineering): Examples from West Bengal and Bangladesh 8.4.1 In-Situ Models 8.4.1.1 Matiari Model - Non-land-Based Household Manufacturing 8.4.1.2 Common Property Resource Management 8.4.1.3 Development of Indigenous Small-Scale and Cottage Industry 8.4.2 Ex-Situ Models 8.4.2.1 Model of Labour Migration 8.4.2.2 Densification of Settlement 8.5 Concluding Notes References Chapter 9: Future Speculations and Challenges 9.1 Perspectives of Future Speculations and Challenges 9.2 Climate Change, Sea Level Rise, and Bank Erosion 9.3 Sociocultural Changes and Bank Erosion 9.4 Future Speculation About the Livelihood Strategies 9.5 Concluding Notes References Correction to: Riverbank Erosion in the Bengal Delta Glossary Index